Continuous conveyor or transfer belts are employed in the transfer systems used in conversion presses for making easy-open can ends that provide sealed closure of cans for the canned food and beverage industries. These transfer systems transport the easy-open ends through and between tooling stages at which various forming or assembly operations are performed on them. Continuous belts are used in various types of conversion presses, including those designed for the high volume manufacture of easy-open can ends used for closure of cans for soft drinks alcoholic and other beverage and the like
The flexible transfer belts that are currently used on easy-open end production equipment are generally made of either rubber or polymer materials. These transfer belts operate at high speeds and may employ various holding mechanisms to hold the easy-open ends in place as they are transported intermittently through the conversion presses. One such mechanism comprises a vacuum system used to hold the easy-open ends in place in circular openings in the belts as these parts travel through the tooling. The easy-open ends nest inside the circular openings in the transfer belt with the outer rim of the ends resting on the upper surface of the belt around the circular opening. The vacuum systems generally apply a normal suction force that compresses the outer rim of the end against the upper surface of the belt. During various parts of the forming process, particularly those that occur after the formation of the curled lip that is used for sealing the end to a can, the curled lip has a relatively sharp outer edge. Over time, by the action of the outer edge against the belt surface, a ring-shaped groove is worn into the upper surface of the transfer belt around the openings. The curled lips of the easy-open ends sink into the ring-shaped groove thereby affecting the performance of the transfer belts, transfer systems, and conversion presses and necessitating the replacement of the transfer belts. Thus, the wear of the transfer belts reduces their operating lifetimes and may result in reduced quality of the easy-open ends and undesirable scrap.
It is desirable, therefore, to provide transfer belts have enhanced wear-resistance around the circular openings and improved belt operating lifetimes.